cmd/internal/gc: cache commonly used Ptrto types
Reduces allocations in the compiler by ~1.5%.
No functional changes. Passes toolstash -cmp.
Change-Id: I2416f7fb0aaf9b7d6783c79e840039ad8fa7b5a3
Reviewed-on: https://go-review.googlesource.com/9419
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/src/cmd/internal/gc/subr.go b/src/cmd/internal/gc/subr.go
index 381079e..8cc140a 100644
--- a/src/cmd/internal/gc/subr.go
+++ b/src/cmd/internal/gc/subr.go
@@ -1546,10 +1546,25 @@
return binary.LittleEndian.Uint32(h[:4])
}
-func Ptrto(t *Type) *Type {
- if Tptr == 0 {
- Fatal("ptrto: no tptr")
- }
+var initPtrtoDone bool
+
+var (
+ ptrToUint8 *Type
+ ptrToAny *Type
+ ptrToString *Type
+ ptrToBool *Type
+ ptrToInt32 *Type
+)
+
+func initPtrto() {
+ ptrToUint8 = ptrto1(Types[TUINT8])
+ ptrToAny = ptrto1(Types[TANY])
+ ptrToString = ptrto1(Types[TSTRING])
+ ptrToBool = ptrto1(Types[TBOOL])
+ ptrToInt32 = ptrto1(Types[TINT32])
+}
+
+func ptrto1(t *Type) *Type {
t1 := typ(Tptr)
t1.Type = t
t1.Width = int64(Widthptr)
@@ -1557,6 +1572,32 @@
return t1
}
+// Ptrto returns the Type *t.
+// The returned struct must not be modified.
+func Ptrto(t *Type) *Type {
+ if Tptr == 0 {
+ Fatal("ptrto: no tptr")
+ }
+ // Reduce allocations by pre-creating common cases.
+ if !initPtrtoDone {
+ initPtrto()
+ initPtrtoDone = true
+ }
+ switch t {
+ case Types[TUINT8]:
+ return ptrToUint8
+ case Types[TINT32]:
+ return ptrToInt32
+ case Types[TANY]:
+ return ptrToAny
+ case Types[TSTRING]:
+ return ptrToString
+ case Types[TBOOL]:
+ return ptrToBool
+ }
+ return ptrto1(t)
+}
+
func frame(context int) {
var l *NodeList
